Previous reports suggest that certain immune responses, including the delayed cutaneous hypersensitivity (DCH) reaction, can be altered by hypnotic suggestion. The proposed study aims to replicate and extend these findings by using modern immunologic methods for the assessment of the cellular immune response, by controlling for subjects' level of hypnotizability, and by studying subjects in a controlled setting. Twelve healthy male and female volunteers, ages 18-50, will be selected for high hypnotizability and admitted to the Clinical Research Center for the experimental procedures. Subjects will be randomly assigned to one of two experimental groups: hypnosis with the suggestion to suppress or with the suggestion to enhance the DCH response in one arm. Following the initial hypnotic induction, all subjects will receive simultaneous intradermal injections of several skin test antigens in both arms using a commercial skin test device. Following this, the subjects will be hypnotized twice daily and the suggestion given to enhance or suppress the response in one arm, the other arm serving as a control. All subjects will be assessed for hypnotizability and handedness using standard measures. Measures of the local immune response will include gross examination, measurement and microscopic examination of biopsies obtained from DCH reactions at the test sites. Skin test reactions from left and right arms will be compared using appropriate univariate and multivariate multiple sample comparison techniques. The demonstration that behavioral interventions can alter the immune response could have important implications for clinical and basic science. Alternatively, definitive negative results could also prove useful, if only to rule out a behavioral component in such phenomena.